Introducing switched antenna transmit diversity for high speed uplink packet access

Abstract

3GPP is investigating uplink transmit diversity alternatives for HSUPA. This paper addresses uplink transmit diversity from the perspective of open loop where additional feedback information is not available. Furthermore, the focus will be on switched antenna transmit diversity where only one antenna is active at the time even though UE is equipped with multiple transmit antennas. Five different algorithms are presented and benchmarked in system level in various conditions against baseline performance without Tx diversity. The studies show achievable gains when the UE velocity is low but practical algorithms get only fraction of the possible gain and improper algorithms can lead to even performance loss.